1. Field of the Invention:
This invention relates to a ferrule holding device for an optical fiber connector.
2. Description of the Prior Art:
In order to connect optical fibers by means of an optical fiber connector with less transmission loss, it is important to bring their ground end faces into close contact with each other highly coaxially without any clearance between whole end faces. For this purpose, a connector hitherto used has been constructed as shown in a longitudinal sectional view of FIG. 1.
In more detail, optical fibers 1 and 2 having exposed end faces 1a and 2a are centrally held in ferrules 3 and 4 highly coaxially with each other and the ferrules 3 and 4 are inserted into a sleeve 7 which has been movably supported in a sleeve holding body 5a of one connector body 5. In this manner, the ferrules 3 and 4 and hence the optical fibers 1 and 2 are kept highly coaxially to each other with a reforming effect of the sleeve 7. On the other hand, the ferrules 3 and 4 are provided with support flanges 3a and 4a which are retained by springs 8 and 9 interposed between the flanges and retention sleeves 10 and 11 threadedly engaged in the connector bodies 5 and 6, thereby maintaining the end faces 1a and 2a of the optical fibers 1 and 2 supported in the ferrules 3 and 4 in close contact with each other with the aid of spring forces of the springs 8 and 9.
With the above arrangement, however, if there is any dust on the end faces 1a and 2a of the optical fibers in case of releasing the connection of the fibers or other cases, the end faces abut against each other through the dust which would obstruct the close contact of the end faces to increase the transmission loss. It is therefore necessary to clean the end faces of the optical fibers at any time. In general, however, it is difficult to clean the end face because a tip end of the one ferrule 3 is positioned in the sleeve 7 remote from its end in order to keep the fibers coaxial. It is also difficult to clean the end face of the fibers on the side of the other ferrule 4 even exposed out of the sleeve 7 as it is fitted in the connector body 5.
In order to facilitate cleaning the end faces of optical fibers, the retention sleeves 10 and 11 are adapted to be threadedly engaged with the connector bodies 5 and 6. After the retention sleeves 10 and 11 have been removed from the bodies, the springs 8 and 9 are removed to take out the ferrules 3 and 4. With this arrangement, however, the connector bodies are complicated in construction. Moreover, there is a risk of the retention sleeves 10 and 11 being loosened to change the contacting force between the end faces of the optical fibers so as to make unstable the connection of the fibers. In order to avoid this, it is necessary to firmly screw the retention sleeves 10 and 11 into the bodies so as not to permit the retention sleeves to be loosened. In this case, the ferrules cannot be removed from the connector body unless the retention sleeves 10 and 11 are unscrewed along overall length of their screw-threads. Therefore, the assembling and disassembling of the connector are troublesome and time-consuming. Moroever, a particular precaution is needed so as not to assemble the connector without tightening the retention sleeves 10 and 11.